Nonenzymatic sensor for determination of glucose in blood plasma based on nickel oxyhydroxide in a microfluidic system of cotton thread

摘要

The development of new non-enzymatic method for determination of glucose using a screen-printed electrode modified with carbon nanotubes and nickel ions (SPCE/CNT-Ni) as an amperometric detector in a microfluidic system based on textile threads is described. Excellent adsorption performance for nickel ions was achieved using pretreated CNT under acid conditions. Good voltammetric stability and repeatability were verified for electrochemical process associated to Ni(OH)(2)/NiOOH redox couple. In presence of glucose a significant catalytic effect related with chemical oxidation of carbohydrate by NiOOH was observed. Microfluidic system was assembled on a 3D-printed platform constructed with ABS polymer and nine cotton threads parallel arranged. The device provided a stable flow rate of carrier solution (0.697 mu L s(-1)) and low-consumption of samples and reagents (volume of injection of 1.5 mu L). Under optimized conditions (0.01 mol L-1 of NaOH as carrier solution, amount of modifier and + 0.45 V of potential of detection) a linear dynamic range (LDR) from 25 to 1000 mu mol L-1 was obtained, with a limit of detection (LOD) 3.9 mu mol L-1, limit of quantification (LOQ) of 13 mu mol L-1 and an analytical frequency of 110 injections per hour. Effect of concomitants species such as ascorbic acid, dopamine and uric acid has been investigated. The proposed method was successfully applied for determination of glucose in a commercial blood serum human (original and spiked) sample.